We have developed the hardware and software capability for the computer aided measurement and three-dimensional reconstruction of identifiable invertebrate neurons. The objective of this grant is to use this system for a continued study of the lobster stomatogastric nervous system. We want to examine identifiable neurons for their geometrical consistency from preparation to preparation. We want to make measurements of the anatomical parameters of these cells such as branch points and number of spines. We plan to study the synaptic loci by three dimensional reconstruction from serial electron micrographs. We hope to combine the structural analysis with electrophysiological data to predict the intraneuronal flow of current in the processes. Finally, we would like to use this analysis to provide us with models which can be incorporated into some of the digital simulations of small networks presently available.